Blogs have emerged as an innovative tool for sharing information and knowledge, and they command significant interest from information technology (IT) users as well as providers. Our study establishes a research framework to provide an understanding of the factors affecting knowledge sharing among bloggers in online social networks. The research results indicate that bloggers’ trust, strength of social ties, and reciprocity all have a positive effect on their knowledge-sharing behavior. Further, the impact of each factor on such behavior varies by gender. Our results provide evidence that offline expected social norms tend to persist in the online blogosphere and that gender differences need to be considered as a significant factor in understanding the IT usage behavior in the context of social capital theory. For IT managers and blog service providers, our results also highlight the importance of being gender aware in an effort to elicit participation from all constituent members for the successful adoption and usage of blogs as a knowledge-sharing mechanism.